Answer:
The yellow leaf was not exposed to the sun so it can't produce sugar.
Explanation:
The yellow region of the leaf didn't produce sugar because it wasn't exposed to sunlight. Part of the leaf was exposed to the sun, thus this leaf produced sugar, while the yellow part of the leaf did not because it was not exposed to the sunlight.
Discover how strong winds high above the earth called "jet streams" are responsible for steering all weather to and away from us.
Plant cells have a cell wall that adds an additional layer of protection from the external environment.